Work handling apparatus for use with sewing machines



. NOV. 3, 1970 sR w ETAL 3,537,702

WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES Fiied April 1 1968 7 Sheets-Sheet 1 Nov. 3,197.0 R. L. KOSROW ET 3,537,702

WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES Filed April 16, 1968 7 Sheets-Sheet 2 R. L. KOSRQW El AL 3,537,702

WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES Filed April 16, 1968 7 Sheets-Sheet 3 N News 1970 KosRow mL 3,537,702

WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES Filed April 16, 1968 7 SheetsSheet 4.

NOV. 3,1970 s w ETAL WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES Filed April 16, 1968 '7 Sheets-Sheet 5 Nov. 3, 1970 os ow ETAL 3,537,702

WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES.

Filed April 16, 1968 7 Sheets-Sheet 6 NOV. 3,1970 R, KOSRQW ETAL 3,537,702 WORK HANDLING APPARATUS FOR USE WITH SEWING MACHINES I Filed Aprii 1a, 1968 x 7 Sheets-Sheet 7 JOCFZOU 30 6L oo o: 4 TFI EOFOZ United States Patent Oflice 3,537,702

U.S. Cl. 271--1 17 Claims ABSTRACT OF THE DISCLOSURE Apparatus adapted to grip a limited area of the forward portion of a work piece, such as that which has passed through the stitch forming region of a sewing machine, to then straighten out or flatten a substantial width of said forward portion of the work piece, and to then deposit the work piece at a receiving station. Such receiving station may be a stacking bar, and the work piece may be deposited thereon, with substantially equal lengths depending from the opposite sides of the bar. The apparatus has various members operated by power supplied either in pneumatic, hydraulic or electrical form for performing the various operations mentioned above, including the conveying of successive work pieces through a substantial distance in the course of transferring them from one region to another. Means are provided for making various adjustments of the extents of movement of certain members to adapt the apparatus for the handlinge and proper delivery of work pieces of different sizes and configurations.

This invention relates to apparatus adapted to transfer flat flexible work pieces from one location to another location. It is capable of quickly and properly delivering successive work pieces to a depositing station, such as a stacking bar or the like at, for example, the completion of a stitching operation.

An object of the invention is to adapt the apparatus for the handling of work pieces a portion or portions of which may depend from one or more edges of a work support. Heretofore, work pieces located on a work support in such manner could not be handled by gripper type work handling means to deliver them in proper position to a stacking bar or the like.

In accordance with the present invention the work is gripped by a first gripping means in a relatively small area at its forward end, for example, as it is advanced from a sewing machine, and it is then subjected to a smoothing-out and flattening action by a gripper element which swings laterally across the forward end of the work. The first gripping means continues to retain the area of the work which it has gripped, and the swinging gripper element straightens out folds and smooths out the work over a substantial part of the width of the work. Subsequently the two gripping means advance the work bodily through a substantial distance toward and over a stacking bar or the like, and both of the gripping means are then released so as to permit the work piece to be deposited onto the stacker bar or other receiving means.

In the preferred embodiment of the invention, provision is made for automatically controlling the operation of the means for picking up successive work pieces and depositing them in a smooth form onto a stacking bar or the 1ike.'This automatic control over the operation of the apparatus here involved is, in the illustrative embodiment, carried out by the provision of pneumatic devices. It is also, to some extent, carried out by electrical means which are in part put into operation under manual Patented Nov. 3, 1970 control and in part put into operation under automatic control through the action of the pneumatic devices, and which in part control the operation of the pneumatic devices.

It should be understood that means other than the pneumatic devices herein illustrated may be employed for carrying out various operations of the apparatus. For example, hydraulic or electric devices may well be utilized, in lieu of the pneumatic means herein disclosed. Also, for the control of the timing of the operation of certain devices, where the illustrative embodiment makes use of the intervention of the work pieces being dealt with for interrupting an air jet to bring about certain results, there may be utilized a light projecting and a light responsive means to accomplish the same general purpose. Thus certain devices in the system may be brought into play when a work piece prevents the transmission of a beam of light to the light responsive device, while some other function of the apparatus may be produced when the Work piece passes out of the path of the light beam and thus enables the light responsive device to be activated.

With the foregoing general objects and purposes in mind, an illustrative embodiment of the invention will now be described in detail by reference to the accompanying drawings, in which:

FIG. 1 is an elevational view of a supporting standard with a conventional table top for carrying a sewing machine, and in relation thereto the work gathering and conveying means and the frame upon which the work pieces are stacked, this view being taken in a direction perpendicular to the path of movement of the work pieces being stitched;

FIG. 2 is an elevational view of the parts shown in FIG. 1 as seen from the right in FIG. 1;

FIG. 3 is a detail View showing, on a somewhat larger scale, certain pneumatic devices and control means embodied in the invention;

FIG. 4 is a plan view of the apparatus shown in FIG. 2;

FIG. 5 is a detail view, in elevation, showing the work gripping mechanism and transporting means involved in the invention, these parts being shown in their normal position referred to as phase 1;

FIG. 6 is a view similar to FIG. 5 showing thevarious parts in a position in which the gripping members are ready to receive a work piece, this being referred to as phase 2;

FIG. 7 is a view showing the various parts illustrated in FIGS. 1 and 2 in a phase 3 position, in which the work gripping elements are about to release the work that has been gripped and carried toward a stack receiving or holding means, the latter being also partially shown;

FIG. 8 is a plan view of the gripping means of the present invention, with a portion of its carrier shown in section, and with a laterally swingable gripping element being indicated in full lines in its normal position and in broken lines in its laterally shifted position;

FIG. 9 is a side view of the parts shown in FIG. 8 as seen from the left of the latter, certain parts being broken away and shown in section; and

FIG. 10 is a schematic view showing the layout of the electrical and pneumatic devices incorporated in the system.

Referring now to the drawings, the invention has been illustrated in relation to its use in conjunction with an overedge sewing machine of the type disclosed in the pending Kosrow application Ser. No. 564,613, filed on July 12, 1966. It will be understood that the invention is capable of use with any of a large variety of sewing machines, and the one illustrated and referred to is simply typical.

Referring to FIGS. 1, 2 and 4, the sewing unit is designated generally as 11 and involves a sewing machine 12, which may suitably be of the character mentioned above. This machine is suitably mounted on a table structure 13 comprising a pedestal 14 having a conventional floor-engaging support, not shown, and a table top 15 at the upper end of the pedestal. The sewing machine 12 is mounted on this table top. Positioned rearwardly and somewhat toward the left of the table top 15 and the sewing machine, as shown in FIG. 4, is a stack receiving structure designated generally as 16. This may be provided with separate support means or may be connected in any suitable manner with the pedestal structure which carries the sewing machine. It may be disposed in any suitable relationship to the pedestal structure 13 to adapt it to readily receive the work pieces transported from the sewing machine to the stacking region by the devices to be hereinafter described.

As best shown in FIG. 4, the rear edge of the table top 15 may have secured thereto an angle bar 17 to which is pivotally connected another angle bar 18 by means of a screw or bolt 19. The latter enables angular adjustment between the members 17 and 18 to place the stacking apparatus at the desired location in relation to the line of feed of the work pieces being stitched. The sewing machine has a work supporting member 20 along which the work being stitched is advanced by the feed mechanism of the sewing machine, as it its being stitched by mechanism which includes a reciprocatory or oscillatory needle 12a. It is believed unnecessary to describe the sewing machine in further detail as it may be of any of a variety of conventional constructions.

Secured to the rearward end portion of the angle member 18 is another angle member 21, best shown in FIG. 2, which may be secured to a vertically extending plate 22 carried by the vertical portion of angle member 18. To the member 21 there is secured, by screws or the like, a supporting yoke 23 which extends downwardly, rearwardly and toward the left as shown in FIGS. 2 and 4. This yoke constitutes a support member for the mechanism of the present invention which serves to grip the work after it has passed through the sewing machine and to convey such work to the region where it is to be stacked. To the underside of the yoke 23, i.e. toward the front in FIG. 2, there is secured a switch box 25 carrying certain switches for the control of electrical circuits involved in the system. At the top of switch box 25 there is mounted a plugin relay 26 which will be hereinafter described. The support yoke 23 has a laterally extending portion 24 which, as best shown in FIG. 2, cooperates with the upper surface of the angle bracket 21, and is secured thereto by the screws 24a shown in FIG. 4. An extension 24b has pivotally connected therewith the lower end of a rod 27, which may be designated a radius rod because of the manner in which it functions to retain certain parts in a predetermined relation as the work gripping means of the invention is shifted through its various phases. The upper end of rod 27 is connected by an element 27a to an arm 28 of a sector plate 29 to be described in greater detail hereinafter. The arrangement is such that element 27a is adapted to be pivotally connected, by means of a screw 28a, with one or another of a series of openings in the arm 28. The particular point on the radius rod at which the element 27a is secured thereto may be varied. In turn the arm 28 may be adjusted to a number of different positions in relation to the sector plate 29 by means of bolts 29a, which are adapted to cooperate with selected holes in the plate 29. By these means the extent of movement of certain parts may be varied to suit particular requirements, as will be explained hereinafter. The sector plate is pivotally connected by a bolt 29b with the upper end of a rockable supporting arm 34. The latter has its lower end rockably mounted in the support yoke 23 by means of a pivot pin 23a. Extending at substantially right angles to the arm 34,

and rigidly connected therewith, either integrally or otherwise, is another arm (FIGS. 1, 5, etc.) which, as will be explained, is connected with a pneumatic piston which serves to rock the bell-crank formed by the arms 34 and 35.

A rod or bar 32 is secured by a clamping portion 32a extending from the sector plate 29. This clamping portion firmly retains the bar 32 by the tightening of screws 32b. Adjacent the lower end of the rod or bar 32 are two laterally extending shafts 30 and 31. The shaft 31 is retained in fixed, non-rotatable position in relation to the bar 32, while the shaft 30 is adapted for rocking movement in bearing means carried by the bar 32 and in a connecting link 36 at the other ends of the shafts 30 and 31. To prevent longitudinal movement of the shaft 30, it is provided with a collar 30a adjacent one end adapted to cooperate with the member 36, while at its other end an arm 37 is secured to the shaft 30 and arranged to cooperate with the outer surface of the rod 32 (see FIG. 8). Referring to FIGS. 5, 6, and 7, it will be seen that the outer end of the arm 37 is connected by a piston rod 38 with a piston within a cylinder 39. The latter is pivotally secured to the arm 32 by a suitable bolt connection 40.

Secured to the shaft 30 at suitably spaced points are blocks 41. These are secured to the shaft by set screws 41a which enable adjustment of their position longitudinally of the shaft. To the under surfaces of the blocks 41, there are secured the ends of a substantially U-shaped member 42 which, as will be later explained, forms the upper member of a work gripping unit. The various portions of member 42 are designated 42a, 42b, and 420, respectively. To the under surface of the portion 42b, there is attached, suitably by an adhesive, a friction creating element 43. This may be formed of rubber or a plastic adapted to provide frictional resistance to the sliding movement of a work piece being gripped. Cooperating with the upper gripping member 42 are two lower gripping members 44 and 45. The member 44 is secured to a block 44a adjustably mounted on and secured to the stationary shaft 31. As shown, the member 44 is preferably parallel with the portion 42a of member 42 and is arranged to have the upper surface of its free end hold a work piece against the friction element 43 when the latter is in its active position. Member is swingably mounted on a block 45a, which is secured to the shaft 31 preferably by means of a set screw which enables adjustment of the block 45a in relation to the block 44a to which the member 44 is secured. A bolt or screw 45b provides a pivotal connection of the arm 45 with the block 45a. At the upper end of the arm 45, as it is shown in FIG. 8, it is provided with an extension 450 which has connected therewith the end of a piston rod 46. The latter has a U-shaped extension 46a at its left end which straddles the upper end of the arm 45c and is pivotally secured thereto by a screw or bolt 46b. The piston rod 46 extends into a cylinder 47 and has a piston element (not shown) secured thereto within said cylinder. The latter has an extension at its right end (FIG. 8) which is pivotally connected by means of a screw or bolt 47b with a shoulder on a bracket 47a secured to the bar 32.

As will be later explained, suitable controls are provided for introducing air into the cylinders 39 and 47 to bring about the desired movements of the gripping means described above in relation to the work to be removed from the work supporting surface of the sewing machine and deposited on a suitable stacking bar, such as shown at 51. It may be mentioned at this time that the piston within the cylinder 39 is operated at the desired time when the bar 32 has been swung into the position shown in FIG. 6. This will bring about the downward rocking of the upper gripping element 42 against the work to be picked up and urges the latter into cooperation with the lower gripping elements 44 and 45. Element 44 grips the work in a definite region while element 45 then urges successive portions of the work against the portion 42b of the upper gripping member as the element 45 swings from the full line position shown in FIG. 8 to the broken line position shown therein. Such swinging, as has been explained above, is caused by the piston within the cylinder 47 when air is introduced into the latter in the manner to be later explained.

The rod 32 and the arm 34 will normally be in the position shown in FIGS. 1, 2 and 5. However, at an appropriate time in the operation of the machine, these members will first swing into the position shown in FIG. 6, which is that in which the gripping elements are adapted to grip the work to be stacked as delivered from the sewing machine, and then into the position shown in FIG. 7 where the gripping means are ready to release the work and deposit it on a suitable support to be described. The swinging of the rod 32 and the arm 34 in the manner mentioned, is brought about by a piston within the cylinder 48 which is suitably secured to the lower end of the member 23. A piston rod 49 extending upwardly from the piston within the cylinder 48 is connected by a member 50 with the laterally extending arm 35 of the bell-crank member 34, 35. Air will be introduced into the lower end of the cylinder 48 to urge the piston upwardly from the position shown in FIG. to that shown in FIG. 6 when suitable control means is operated, either manually or automatically, when a work piece is about to be removed from the sewing machine and delivered to a stacking position. When the rod 32 and arm 34- are in the position shown in FIG. 6 the piston within the cylinder 39 will be operated to swing the upper gripping member 42 downwardly against the work and against the lower gripping elements 44 and 45. At this time, air will be introduced into the cylinder 47 to urge the piston rod 46 toward the right (FIG. 8) and swing the gripping element 45 through a suitable angle in a clockwise direction. This movement of the gripping element 45 serves to smooth out the portion of the work that is engaged by the part 4% of the top gripping element 42. When this is accomplished, air is introduced into the upper end of the cylinder 48 to urge the piston therein, which is connected with the piston rod 49, in a downward direction into the position shown in FIG. 7. This operation of the piston within the cylinder 48 serves to swing the arm 34 through a substantial angle into the position shown in FIG. 7. At the same time the rod 32 will be swung from the position shown in FIG. -6 to that shown in FIG. 7. This swinging of the rod 32 results from the connection of the rod 27 at its lower end to the extension 2411 of fixed member 23', and the connection of its upper end to the arm 28 carried by the plate 29 which turns about its axis 2%.

As shown in FIG. 7 and other views, the extent of movement of the upper end of the rod 27 and the extent of swinging of the rod 32, as a result of the swinging of the arm 34 in the manner explained, may be varied by the adjustment of screw elements 28a and 29a into the different openings through the arm 28 and plate 2%. Such adjustment enables the stacking mechanism to swing through the desired stroke to deposit work pieces of different lengths, that may be dealt with at different times in the use of the apparatus, onto the stacking bar 51 with substantially equal lengths of the work piece on opposite sides of the stacking bar.

As best shown in FIGS. 1 and 2, the stacking bar 51 is mounted on the top of a vertically extending frame structure having vertical supports 52a and 52b. At the top ofthe latter there is a cross bar 51a which carries the stacking member 51. Extending rearwardly and toward the right in FIG. 1, and forwardly and toward the right in FIG. 2, are frame elements 53a and 53b connected at their lower ends to the members 52a and 52b, respectively, and also connected with the latter at their intermediate points by members 54a and 54b. The upper ends of the members 53a and 53b are connected by a horizontal cross member 55. Extending upwardly from the members 53a and 53b to a distance slightly above the cross member 55 are. plates 56a and 56b. In these there is journaled a rotary member or tubular shaft 57. The latter carries a pulley 57a at its right end (FIG. 2) which is connected by a belt "58 with a pulley mounted on the shaft of a motor 59 suitably secured to the support member 53b. As will be explained, the motor 59 serves to drive the tubular shaft 57 continuously in a counterclockwise direction (FIG. 7) so as to facilitate the movement of the work piece W by the gripping members from the discharge side of the work supporting table into the position shown in FIG. 7. At this time the gripping member 42 is rocked upwardly away from the gripping members 44 and 45 so as to release the work and permit it to drop onto the stacking bar 51. The continuous rotation of the tubular shaft 57 insures the delivery of the righthand portion of the work piece into a position from which it will drop on the righthand side of the stacking bar, while that end of the work that is released by the gripping means will drop on the lefthand side of the stacking bar.

Turning now to FIGS. 3 and 10, various controls over the flow of air to the several piston cylinders described above will now be discussed. Air from a suitable source is delivered to the equipment through a line 60 into a valve 61, which is of a character designated four-way air bleed pilot valve of well-known construction. As shown in FIG. 10, this valve is adjusted to deliver the air to a line 62. This is connected with a solenoid valve 63, the electrical control of which will be hereinafter described. From this valve the air is delivered to line 64 and through a flow control valve 65 to one end of the cylinder 48 which, as has been explained, is the one that serves to swing the arm 34. When the adjustment element of valve 61 is swung into the broken line position indicated in FIG. 10, the air being supplied to line 60 will be delivered through line 66 and a solenoid valve 67, then through a line 68 and flow control valve 69 into the opposite end of the cylinder 48. Through these connections the piston within the cylinder 48 will be urged at the proper times in the desired direction to cause the swinging of the arm 34 in the manner explained. A line 70 also leads from the valve 61, and this is connected with a bleeder valve 71 which is operated by the lower end of the screw element 73 when the piston in cylinder 48 reaches the desired lowermost position. Through suitable adjustment of the screw 73 the extent to which the piston rod 49 is moved downwardly into cylinder 48 may be varied and thus vary the extent of swinging movement of the arm 34.

Also a bleeder line 74 extends from the side of valve 61 coordinated with the broken line position shown. This line 74 extends to a solenoid-operated bleeder valve 75 which Will be operated at appropriate times in the manner to be explained. A branch line 76 extends from line 62 to one end of the cylinder 47 of the piston which causes the swinging of the spreader member 45 (FIG. 8) of the work gripping mechanism. Line 77 similarly branches off from line 66 to the opposite end of the cylinder 47. Moreover, lines 78 and 79 branch off of the lines 76 and 77 to the opposite ends of the cylinder 39 which causes the rocking of the upper gripping member 42 toward and away from the lower gripping elements 44 and 45. The means for controlling the flow of air into these cylinders will be later explained.

Turning now to the electrical system involved in the apparatus of the present invention, this is shown schematically in FIG. 10. A source of volts, 60 cycle alternating current designated HT-l is connected by a line 81 and a cross line 82 with one terminal of the motor 59, described above, which serves to drive the bar 57. The opposite terminal of motor 59 is connected by a line 83 with ground at GT-l. A switch, not shown, may suitably be provided in the circuit just described to turn the stacker motor 59 on and off as desired. Normally, the motor will remain in operation so long as the stacker system is desired to be in operation.

For control of the various pneumatic devices described above, to bring about the conveying and depositing of successive work pieces, a switch 84 is provided. This may be either manually or automatically operated. Manual operation may be performed by the hand, the knee, or the foot of the operator, while automatic operation may be controlled by an electric eye, for example, which becomes effective as a work piece being stitched leaves the stitch forming zone of the sewing machine. Switch 84 is connected at one end with ground at GT-X and at its other end, when closed, with a solenoid 85, the opposite terminal of which is connected with a current source HT-X. When the solenoid 85 is thus operated a switch 86 will be closed and thus complete a circuit from HT-X to and through a solenoid 87 over to ground at GT1. Activation of solenoid 87 will then close the switch 88 to complete a circuit from source HT1 through line 81 and over to and along line 89 to a solenoid 90 connected with the valve 67. The opposite terminal of solenoid 90 is connected through line 91 to ground at 92. In parallel with the circuit just described is one extending through branch line 89a, solenoid 90a of valve 63, and line 91a to ground at 92.

If switch S2 is closed, a pair of further, parallel, circuits will be established supplying current to the solenoids 90, 90a of valves 67 and 63, respectively. Switch S2 is retained in its open position by the engagement of a projection 29c carried by the plate 29, which as described above turns about the axis 2% when the member 34 is rocked by the action of the piston within the cylinder 48. It will be noted from FIG. that the projection 290 is engaged with an arm connected with the switch S2. This switch is normally closed but is pressed into an open condition when the projection 29c acts upon the operating arm or button as described. When the member 34 is swung into the position shown in FIG. 6, the projection 290 is disengaged from switch S2 so that the latter closes, while at the same time projection 29c acts upon the arm of switch S-3 to close the latter. Prior to this, when the parts were in the position shown in FIG. 5, the switch S3 was in its normally open position.

The closing of switch S2 completes the above-mentioned parallel circuits. These extend from source 96 through line 95, line 94, switch S2, line 93 and lines 89 and 89a, respectively, over to and through solenoids 90 and 90a and through line 91 and 91a to ground at 92. When switch S3 is closed by the action of projection 290 as described, a circuit will be partially completed from source 96 through line 95 and line 97 to and through the switch S-3 and downwardly through a line 98 to switch S1. This, as shown in FIG. 10, is held in an open position by an extended piston rod 99 connected with a piston within a cylinder 100 which is adapted to receive air I through a line 101 from a receiver 102. The latter is arranged to receive air under pressure from a jet 103 whenever no work piece is interposed between the receiver and the air jet, and when the pilot valve 61 is in the position in which air under pressure is fed from source 60 to line 62 and then line 76. It may be mentioned at this point that the receiver 102, as shown in FIGS. 8 and 9 is mounted on a bracket 102' secured to the swinging gripping element 45. The arrangement is such that whenever a work piece, coming between the members 42, 44 and 45, is brought into the path of the air from jet 103, it will serve to interrupt the passage of the air jet to the receiver 102, and will thus cause the piston rod 99 to retract and bring about the closing of switch S-l.

When the stacking mechanism is in its normal position, i.e., has completed a stacking operation and is awaiting the operation of switch 84 to begin a new stacking operation, the various cylinders 39, 47 and 48 will be in the positions shown in FIGS. 5 and 8. This means that the piston rod of cylinder 48 is projected outwardly to a substantial extent from the latter but not to its full extent. Clamping cylinder 39 will have its piston rod retracted and cylinder 47 will have its piston rod extended, so that the spreading member 45 of the gripping means is in the full line position shown in FIG. 8.

Now when a work piece is approaching the end of a stitching operation and is about to be ready for stacking, the switch 84 will be operated either manually or automatically, in the manner explained above, to complete a circuit through solenoid 85. This in turn will complete a circuit through solenoid 87 to and through the solenoids 90 and 90a of the valves 67 and 63. The operation of valve 67 in this way will interconnect the air lines 66 and 68, so that the pressure that has been maintained in the upper end of cylinder 48 will be relieved and this air will be discharged through lines 68 and 66 and an outlet in pilot valve 61. At the same time, air from the supply line 60 will be delivered through the valve 61 to line 62, and through valve 63 into line 64 and then into the bottom of cylinder 48. This will cause the upward movement of the piston within the cylinder 48 so that the members 32 and 34 and their interconnected parts will be shifted from the position shown in FIG. 5 to that shown in FIG. 6. It should be noted in this connection that the switch arm 84 need not be retained in its closed position for any substantial length of time. This is because the circuit to and through solenoids 90 and 90a, of valves 67 and 63, will remain closed even after relay is deenergized. This is due to the fact that the projection 290 on the plate 29 will have shifted from the position shown in FIG. 5 to that shown in FIG. 6, thus bringing about the closing of switch S2 which completes said parallel circuits from source 96 to and through the solenoids and 90a to ground at 92. The switch 84 should be kept closed long enough to insure the closing of the above-mentioned circuits through switch S2. However, if desired, well-known timing means could be provided for retaining the switch 86 closed for the period required, even though the switch 84 is not held closed for the time required to close switch S2.

With the gripping mechanism in the position shown in FIG. 6, a work piece is either automatically or manually advanced into a position between the upper and lower gripping elements, and it then serves to intercept the jet of air being discharged by nozzle 103 so that it does not enter the receiver 102. When this occurs, the air in the cylinder is discharged into the atmosphere and the switch S-1 is urged into closed position by a suitable spring (not shown). At this time both switches S-1 and S3 are closed so that a circuit is completed from terminal 96 through switch S-3, then switch 84, then upwardly through line 105 and over to solenoid 106 and to ground at 106a. Solenoid 106 operates the bleeder valve 75, previously mentioned, which is connected through line 74 with the pilot valve 61. The opening of bleeder valve 75, to connect line 74 to outlet 75a, lowers the pressure in line 74 and within a chamber in the pilot valve, so as to cause the pilot valve to swing into the broken line positron schematically shown in FIG. 10. This means that air under pressure from line 60 will now be delivered into line 66, then through valve 67 and line 68 into the upper end of the cylinder 48. Since the pressure in lines 62 and 64 are now lowered as a result of the shifting of the pilot valve 61, the piston within cylinder 48 will move downwardly and will thus cause the arm 34 to rock in a counterclockwise direction into the position shown in FIG. 7. This, of course, simultaneously causes the swinging of the bar 32 into the position shown in FIG. 7, so that the work which has been gripped will be placed in a suitable position over the stacking bar 51.

In connection with the foregoing it should be noted that the swinging of the pilot valve 61 into the upper schematically indicated position, in which air under pressure is delivered through line 77 to the right end of cylinder 47 (FIG. 10), will cause the piston within this cylinder to be urged toward the left in FIG. 10, or toward the right in FIG. 8. As a result, the gripper arm 45 will be swung from the full line to the dotted line position shown in FIG. 8, thus serving to spread out the portion of the work piece that has been gripped. Also, at

this time, air from the line 77 will flow through line 79 into the upper end of cylinder 39 thus urging the piston in the latter downwardly to cause the upper gripping member 42 to swing downwardly into engagement with the work and to urge the latter against the lower gripping members 44 and 45. It should be noted in connection with the foregoing, suitable flow control valves are provided for insuring the proper sequence of operation of the piston members described. Thus, the cylinder 39 becomes effective quickly to urge the upper gripping member 42 downwardly in the manner explained, and the cylinder 47 which causes swinging of the gripping element 45 is then rather promptly brought into play to bring about the smoothing action. After a slight delay, brought about by the control valves, the piston within cylinder 48 will be operated to cause the swinging of the rod 32 and arm 34 from the position shown in FIG. 6 to that shown in FIG. 7.

When the parts reach the position shown in FIG. 7 the screw element 73 will strike the member 71 to operate the bleeder valve 71a and thus cause air to be discharged from the lower side of pilot valve 61 so that this valve will swing back into the full line position shown schematically in FIG. to prepare the system for the next cycle of operations. This final phase of the cycle under discussion is initiated by the introduction of air under presure through line 62, line 64 and valve 65 into the lower end of cylinder 48 so as to bring about the return swinging movement of the rod 32 and the arm 34 into the position shown in FIG. 5. It should be mentioned that, prior to this action of the piston within cylinder 48, air under pressure from pilot valve 61 will have been delivered through lines 76 and 78 into the lower end of clamping cylinder 39, thus swinging the upper gripping member 42 upwardly to release the work. At or about the same time, air under pressure will be delivered into the left end of cylinder 47 (FIG. 10) to cause the gripper element 45 to swing back into its full line position.

Upon completion of the final phase of the cycle of operation of the stacking means, as described above, the various devices will be in the positions schematically shown in FIG. 10, and the system will be ready for the receipt of a new signal to bring about the next cycle of operation which will serve to stack the next work piece that has been dealt with by the sewing machine.

What is claimed is:

1. Work handling mechanism for transferring flexible, substantially flat pieces of work from a work support to a delivery station which comprises a movable member, work gripping means carried by said movable member, said gripping means comprising an element adapted to engage one surface of the work over a substantial area across the same, and two elements adapted to engage the other surface of the work, one of said two elements constantly engaging a particular small area of said other surface of the work as the latter is gripped, while the other of said two elements has a portion thereof movable along said other surface of the work to urge successive portions of the same against said first-mentioned element, means for causing all of said elements to engage the work, means for shifting said other of said two elements to carry said movable portion thereof along said other surface of the work, means for moving said movable member first in a direction to carry said work gripping elements toward said work support and then in a direction toward said delivery station, said elements being in their active gripping position during said movement toward the delivery station, and means acting upon at least one of said work gripping elements to cause release of the work at said delivery station.

2. Work handling mechanism as set forth in claim 1, having means subject to the presence or absence of work in a predetermined area for at least partly controlling the operation of said work gripping means and the movement of said movable member.

3. Work handling mechanism as set forth in claim 1, in which means are provided for varying the extent of movement of said movable member to adapt said mechanism for the proper depositing at the delivery station of work pieces having different lengths.

4. Work handling mechanism as set forth in claim 1, in which said other of said two elements is a pivoted element having a free end shiftable along an arc of substantial radius, and means for imparting pivotal movement to said pivoted element to carry said free end from a point adjacent to the area in which said one of said elements engages the work to a point spaced laterally from said area.

5. Work handling mechanism as set forth in claim 1 in which said first-mentioned element of said gripping means has two arms extending in spaced relation to each other and a laterally extending portion connected with said two arms.

6. Work handling mechanism as set forth in claim 1 in which pneumatically operable means is provided for moving said movable member.

7. Work handling mechanism a set forth in claim 1 in which pneumatically operable means is provided for moving said first-mentioned element of the gripping means into engagement with one surface of a work piece to be transferred.

8. Work handling mechanism as set forth in claim 1 in which pneumatically operable means is provided for moving said other of said two members to carry a portion thereof along the adjacent surface of the work.

9. Work stacking mechanism associated with a sewing machine arranged to receive pieces of work stitched by said sewing machine and deliver the same to a stacking region, which comprises: a swingable member, work gripping means carried by said member and shiftable thereby from a work receiving position in the stitching region of the sewing machine to a work delivering position upon the swinging of said member, power means for swinging said member to first carry said gripping means from an idle position into the work receiving position, then to the work delivering position and finally back to said idle position, power means for causing the gripping means to grip a work piece at the receiving position and release the same at the delivering position, and movable means embodied in said gripping means arranged to flatten and smooth out the work in the region in which it is gripped.

10. Work stacking mechanism as set forth in claim 9 in which means are provided for controlling said power means for swinging said swingable member, said control means being responsive at least in part to the presence and absence of a work piece in a particular region.

11. Work stacking mechanism as set forth in claim 9 in which means are provided for partly controlling the operation of said gripping means in response to the movement of said swingable member into a predetermined position.

12. Work stacking mechanism as set forth in claim 9 in which means are provided for detecting the presence or absence of a work piece in a particular region adjacent the sewing machine, and means controlled by said detecting means for controlling the operation of said power means for swinging said swingable member and said power means for causing the gripping elements to released a work piece.

'13. Work stacking mechanism as set forth in claim 12 in which said detecting means controls in part the movement of the means for smoothing out the work.

14. Work stacking mechanism as set forth in claim 10 in which adjustable means are provided for selecting the extent of swinging movement of said swingable member in the direction toward said work delivering position.

15. Work stacking mechanism as set forth in claim 9 in which a rotary member is provided in the path of movement of the work gripped by said gripping elements, and means for constantly driving said rotary member.

16. Work stacking mechanism as set forth in claim 9 in which said power means for swinging said swingable member comprises a fluid operated piston within a cylinder, and solenoid operated valves for controlling the flow of fluid into and out of the opposite ends of said cylinder.

17. Work stacking mechanism as set forth in claim 16 in which another valve is provided for limiting the extent of movement of said piston in the direction in which it swings said swingable member toward the work delivering position, and adjustable means connected with said piston for operating said last-mentioned valve.

References Cited UNITED STATES PATENTS 2,684,165 7/1954 Hill 214654 5 3,371,631 3/1968 Rockerath 112-12129 3,209,922 10/1965 Melvin. 3,355,074 11/1967 BreWin et a]. 112-121.29 2,861,699 11/1958 Youmans.

10 EVON C. BLUNK, Primary Examiner ROGER S. GAITHER, Assistant Examiner US. Cl. X.R. 

